Vacuum responsive governing means for internal combustion engines



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VACUUM RESPONSIVE GOVERNING MEANS FOR INTERNAL COMBUSTION ENGINES Patented Nov. 28, 1 939 UNITED -STATES PATENT OFFICE VACUUM RESPONSIVE GOVERNING MEANS FOR INTERNAL COMBUSTION ENGINES poration of Delaware Application June 13, 1936, Serial No. 85,014

10 Claims.

This invention relates to the manner of and means for regulating and controlling the feeding of fuel to internal combustion engines and more particularly to the manner and means for controlling and regulating the fuel pumping unit in accordance with variations in vacuum in the intake manifold. v

A type of fuel feeding means commonly employed, particularly in connection with engines of the Diesel or semi-Diesel type in which the fuel is injected directly into the cylinder or combustion chamber in a highly atomized state, comprises a pumping unit having a reciprocating, biased pump plunger for each engine cylinder delivering extremely small, metered quantities of fuel in timed relation to the engine cycle; the metering of the fuel in accordance with the engine requirements being accomplished by means of a vacuum responsive governing device and a positioning means operatively connected with the pump plungers or their actuating means and "with the governing device to be actuated by the latter so that movement of the governor will correspondingly vary the stroke of the pump plungers.

The common practice in connection with the foregoing arrangement in order to maintain the governing mechanism in continuous and operative engagement with the pump plungers or their actuating means is to use either a relatively strong spring to bias the movable element of the governor, which is usually a piston, together with the positioning means and the associated mechanism or to bias the movable governor element by means of a relatively weak spring and to include an additional ,fbiasing means operatively associated with the positioning means or the interconnecting mechanism.

In the first instance, the use of a strong spring materially decreases the sensitiveness of .the governor and renders it extremely difficult if not impractical to adjust for all operating conditions of the engine, and in the second instance in order to maintain the governor sensitive, an additional biasing means must be provided which increases the cost of manufacture and further complicates adjustment of the device.

Consequently, one of the primary objects of this invention is to provide a vacuum responsive governing mechanism which is associated With thepump plungers or their actuating means in such a manner that the aforementioned difdculties are entirely eliminated.

Another object is to associate a vacuum responsive governing device with .a Pump control shaft or rod by means of a simple, direct connection which reduces friction to a minimum and is readily adjustable to control the fuel feed in accordance with the operating conditions.

Additional diiculties have been experienced with the prior art devices and arrangements in which a vacuum responsive governor is operatively associated with the fuel feeding mechanism of an engine in an attempt to maintain a constant fuel air ratio under all conditions of engine operation, due to the fact that the usual arrangements utilized a. vacuum responsive piston biased by an ordinary compression spring so that the piston will move to compress the spring in accordance with the increase in vacuum in the intake manifold caused by the movement of the throttle valve towards closed position. However, with the use of an ordinary compression spring, the curve obtained by plotting piston movement against spring compression is a straight line, while the curve obtained by plotting fuel quantities as ordinates against the vacuum in the intake manifold as abscissa is substantially hyperbolic in form. Consequently, with the use of a single biasing spring, the piston movement only assimilates the fuel vacuum curve in the immediate region in which the straight line curve of piston movement is tangent to the fuel vacuum curve and although the use of two successively acting biasing springs has been used inorder to Obtain different rates of fuel feed for different conditions of engine operation, yet the resulting curve of kpiston movement, even if the springs are selected in order to make the curve of piston movement approximate the fuel vacuum curve, will only assimilate a minor portion of the fuel vacuum curve and, as a result, the device cannot be adjusted to obtain a constant fuel air ratio and satisfactory engine performance under all conditions of operation.

Therefore another primary object is to provide a vacuum responsive governing device which will so closely assimilate the substantially hyperbolic fuel vacuum'curve that the corresponding and resulting fuel regulation will conform with engine requirements under all operating conditions, and a substantially constant fuel air ratio will always be maintained.

Another object is to provide a vacuum responsive governing device embodying a novel arrangement of parts which cooperate to render the device extremely sensitive, durable and cheap` to manufacture.

The invention accordingly consists ofthe various features of construction, combinations of elements and arrangements of parts as more particularly pointed out in the appended claims and in the detailed description, reference being had to the accompanying drawing, in which:

Fig. 1 is a diagrammatic elevational view of an internal combustion engine embodying the invention;

Fig. 2 is a vertical sectional view of a vacuum responsive governor taken on line II-II of Fig. 3;

Fig. 3 is an elevational view of the fuel pumping means and governor with parts broken away to show the details of construction;

Fig. 4 is a fragmental sectional view of a pump actuating and regulating means takenA on line IV-IV of Fig. 3; and

Fig. 5 is a vertical sectional view of a modified form of governing device.

Fig. 1 illustrates a conventional internal combustion engine I of the Diesel or semi-Diesel type having a fuel injection pumping unit 2 delivering fuel in metered quantities through pipes 3 to the individual engine cylinders 4, an intake manifold 6 including the usual throttle valve 1, which may be actuated mechanically or by any suitable governing device not shown, an air cleaner 8 connected to the inlet end of manifold 6, and a governing device I3 operatively associated with the intake manifold by means of pipes 9 and II so as to be responsive to variations in vacuum therein and with the pump control shaft I2.

The fuel pumping device employed, reference being had to Figs.l 3 and 4, comprises a casing I5 in which is positioned a plurality of plungers I4, there being one for each'engine cylinder, actuated on their return or intake stroke by means of springs I6 which always retains each plunger I4 in positive engagement with its tappet mechanism I1. The interior of the pump casing I5 is divided by means of a horizontal partition I8 into an upper chamber I9 into which the lower ends of the pump plungers I4 extend and a lower chamber 2I in which is positioned the pump cam shaft 22; the partition I8 having vertical bores 23 therein, alined with the pump plungers and their actuating cams, in which the tappet mechanisms I1 are mounted for reciprocation. Each of the tappet mechanisms comprises a hollow piston 24 having alined openings 26 in its side wall through which the pump control shaft or pump positioning means I2 extends, an internally threaded bore 21 in the piston head receives an externally threaded stem 28 having a locking nut 3| thereon and its upper end formed to provide` a nut 29 for turning and adjusting the stem 28 relative to the piston 24, and trunnions 35 extending inwardly from adjacent the bottom of the piston side wall supporting a short shaft or rod 33 on which is rotatably mounted the camv follower or roller 32, the roller being engaged by the high portion of the actuating cam 34 to raise the tappet mechanism and actuate the pump plunger on its injection stroke. The alined openings 26 in the piston through which the control shaft I2 extends are of'such size that the tappet mechanisms may be raised relative to the control shaft.

The control shaft I2 vis mounted for rotation in bearings (not shown) formed in the end walls of the pump casing I5 and has lone end 36 extending into the casing 31, which houses the vacuum responsive governing device, and is provided with any suitable means 38 securing the arm 39 thereto for movement therewith, it being understood that the arm 39 may be made integral with the Shim if it is so desired. The control shaft has formed on its upper surface and in alinement with the vice illustrated vin Fig. 2 comprises a casing 31 having formed therein a vertical cylinder 42 open at its upper end; an elongated piston 44 mounted for vertical movement therein and effectively sealing said end and biased to the position shown by means of three serially arranged and cooperating springs 46, 41 and 48, the weakest spring having its upper end abutting the piston head, the strongest spring 48 having its lower end abutting the bottom of the cylinder 42 and with the adjacent ends of springs 46, 41 and 41, 48 respectively abutting opposite faces of the spring retainers 48 and 5I; a passage formed in the outer wall of the cylinder which has a connection with the pipe II for subjecting the interior of the cylinder beneath the piston to the vacuum within the intake manifold; and a cover 43 provided with a connection 45 to which the pipe 9 is 'transmit the piston movement to said arm; the

stem adjacent its upper end having means 51 such as a groove and washer to prevent the stem from falling out of the cylinder when the arm 39 is removed. The piston head has, in the arrangement shown, a depending boss 58, the head and boss being axially bored to receive a bolt 59 having a head 6I on its lower end against which the stem 56 abuts and the nut 62 on its upper end which coacts with the cover 43 to limit the upward movement of the piston. Obviously, instead of fthe bolt and nut arrangement shown, the piston could be provided with axially extended bosses directly engaging the stem and cover for the purposes above set forth or the upper boss could be formed on the cover 43.

With reference to the pump control shaft I2, it is seen that the fuel feeding action of the pumping'unit is greatest when the flats 4I are in a horizontal position since the tappet roller 32 is always inengagement with the cam 34 and the stroke of the pump plungers is maximum, and that when the control shaft is rotated to move the flats out of their horizontal position the pumping action will be decreased, since the tappets and plungers will be raised relative to the cam 34. In this connection, it should be observed, reference being had to Figs. 3 and 4, that the shape of the actuating cams 34 is such that the pump plungers are maintained in their raised position and out of engagement with the control shaft I2 throughout substantially 270 of cam rotation and it should be obvious that the time interval expressed in degrees of cam rotation during which each plunger is maintained in its raised position will vary, assuming a single pump plunger for each engine cylinder, with the number of engine cylinders. Stated differently. the actuating means for the fuel feeding devices or pump plungers is of such a shape or nature that during the time interval existing between the reception and the delivery of a fuel charge by one of the fuel feeding devices the connection between the remaining fuel feeding devices 'and the control shaft or member I2 is inoperative or that the operative connection between each fuel feeding device and the control shaft or member I2 is disrupted during the time interval existing between the delivery of its fuel charge and the next delivery of a fuel charge by the precedently operated fuel feeding device. The pump plunger biasing springs I6 act through the tappet mechanisms I1, tending to rotate the control shaft I2 so as to maintain the ats 4I in a horizontal position. The control arm 39 is so positioned on the shaft I2 that with the flats in their horizontal position the stem 56 just touches or lightly engages the piston head, the arm 39 being provided with adjusting screws 63 and 64, the latter coacting with a stop 66 formed on the governor casing 31 to determine the full load or maximum stroke of the pump plungers and the former coacting with the piston stem 56 to eliminate any lost motion which mightresult from the adjustment of screw 64 or to vary the initial, relative positions of the arm and piston. The adjustment which eliminates lost motion as above pointed out enables movement of the piston to always produce a corresponding movement of arm 39 and control shaft I2 so that the fuel air ratio is maintained constant throughout the entire range of engine operation.

A boss 61 on arm 39 has connected thereto, by any suitable means, a wire or cable 68 which extends outwardly of the casing 31 for manually actuating the arm 39 downwardly to terminate the' pumping action whenever the operator so desires. A cover plate 69 secured in position by any suitable means closes an opening II provided in the casing 31 adjacent the arm 39 in order to gain access to the adjusting screws 63 and 64.

The modied form of governing device illustrated in Fig. 5 differs from the previouslyl described form in that the cylinder and piston are located beneath the control arm 39, thus eliminating the projection of the piston stem through the cylinder casing and the provision of a seal therefor, and in order to simplify the description corresponding parts are designated by the same reference numerals as follows: casing 31, means 38 for attaching the control arm to the shaft I2, control arm 39, vacuum cylinder 42, coverv 43, springs 46, 41 and 48, spring retainers 49. 5I, piston 44, piston stem 56, adjusting screws 63 and 64, stop 66, cover plate 69, and opening'lI. The connection 12 for subjecting the interior of the cylinder 42 to the vacuum within the intake manifold is located in the cover 43 which closes the open, bottom end ofcylinder 42 and the internally threaded axial bore in the piston top receives the externally threaded lower end 15 of the piston stem 56 which is locked against relative movement by means of nuts 13 and 14. The upper end of the stem 56 is formed with an eye or stirrup 16 loosely receiving the outer end of the control arm 39, the upper portion Vof this stirrup or eye mounting the adjusting screw 63 which functions in identically the same manner as does the corresponding screw in Fig. 2. In fact, the operation and adjustment of this device is functionally identical in all respects to the first described form.

The operation of these devices in connection with the feeding of fuel may be briey summarized as follows: with the engine operating under full load conditions, the throttle valve 1 is fully open, the pressure in the manifold on either side of the throttle valve is substantially the same and consequently the vacuum eiect in the manifold is negligible and the parts will assume the positions shown in Figs. 2 to 5 inclusive with the fuel feed a maximum. However, if the throttle valve is partially closed, the vacuum in the intake manifold will increase and, as a result, the piston 44 will move downwardly compressing one or more of the serially arranged springs 46, 41 and 48, depending upon the extent to which the throttle valve is closed, and will correspondingly move the arm 39 downwardly and rotate the control shaft I2 to raise the pump tappet mechanisms and plungers to decrease the pumping action as hereinbefore described.

The amount of rotation of the control shaft I2 necessary to decrease the rate of fuel feed from the maximum value to the minimum value corresponding to idling conditions ls relatively small, being approximately 40 degrees, and consequently,'in order that a senstive governor may be used, that is, one whose movement in response to small variations in vacuum is comparatively large, means reducing friction to a minimum must be provided for interconnecting the control shaft with the piston so that the piston movement is materially greater than the resultant movement of the control shaft. This result is accomplished by having the arm 39 secured to the control shaft for movement therewith, the latter directly engaging the movable element of the governing device at a material distance from the axis of said shaft. f

Moreover, the use of the rotary control shaft I2 biased to a positionin which the fuel pumping action is a maximum, solely by the action of the means biasing the pump plungers, enables the control arm 39 interconnecting the shaft I2 and lpiston stern 56 to be at all times in continuous an'd lrelatively strong spring to bias the vacuum piston together with the associated mechanism in a continuous and direct engagement with the pump actuating means would materially decrease the sensitiveness of the governor and render its adjustment impractical as it would not be free to y readily respond to small variations in the vacuum.

-The use of three serially arranged and successively stronger springs operating to bias the piston permits the piston movement to be relatively large in response to small variations in vacuum and to closely approximate the substantially hyperbolic fuel vacuum curve obtained by plotting fuel quantities as ordinates and vacuum' in vthe vintake manifold as abscissa. Consequently, the use of such a device will maintain the fuel air ratio substantially constant throughout. the entire operating range of the engine.

The adjusting screw 63 enables the operator to readily vary the fuel air ratio in order to compensate for changes in the air density, such for example, as those resulting from materialvariations in altitude and the adjustment of screw 64 is for the purpose of making the maximum fuel delivery ,conform with fuel characteristics and to compensate for manufacturing discrepancies. However, these two screws cooperate to enable such adjustments without subjecting the vacuum piston to any additional biasing force and without producing any lost motion in the connections between the vacuum piston and the'pump actuating means.

It should be understood that it is not desired to limit the invention to the exact details of construction and operation herein shown and described, for various modifications within the scope of the claims may occur to persons skilled in the art.

It is claimed and desired to secure by Letters Patent:

1. In combination, an internal combustion engine regulator having a movable element and fuel feeding mechanism having a plurality of fuel feeding devices, means for actuating the fuel feeding devices to deliver charges of fuel in a predetermined order, biasing means acting to maintain the fuel feeding devices operatively connected with the actuating means, and a movable control member cooperating with said fuel feeding devices and with said movable regulator element and operative when moved to vary the quantity of fuel delivered by the fuel feeding devices, said actuating means; and fuel feeding devices being so correlated that a single fuel feeding device biasing means acts to restrain movement of the control member in the quantity reducing i direction.

2. In combination, an internal combustion engine regulator having a movable element and fuel feeding mechanism having a plurality of fuel feeding devices, means for actuating the fuel feeding devices to deliver charges of fuel in a predetermined order, biasing means acting to maintain the fuel feeding devices operatively connected with the actuating means, and a movable control member cooperating with said fuel feeding devices and with said movable regulator element 'and operative when moved to vary the quantity of fuel delivered by the fuel feeding devices, said actuating means being of such a nature that movement of the control member in the quantity reducing direction is at all times resisted by a single fuel feeding device biasing means.

3. In combination, an internal combustion engine regulator having a movable element and fuel feeding mechanism having a plurality of fuel feeding devices, m'eans for actuating the fuel feeding devices to deliver charges of fuel in a predetermined order, biasing means acting to maintain the fuel feeding devices operatively connected with the actuating means, and a movable control member cooperating with said fuel feeding devices and with said movable regulator element and operative when moved to vary the quantity of fuel delivered by the fuel feeding devices, said actuating means being of such a nature that a single fuel feeding device biasing means acts to urgesaid control member into the position for causing the maximum rate of fuel feed.

4. In combination, an internal combustion engine regulator having a movable element and fuel feeding mechanism having a plurality of fuel feeding devices, means for actuating the fuel feeding devices to deliver charges of fuel in a predetermined order, biasing means acting to combustion engine regulator having a movable element, fuel feeding mechanism having a plurality of fuel feeding devices, means for actuating the fuel feeding devices to deliver charges of fuel in a predetermined order, a movable control member cooperating with the fuel feeding devices and with the movable regulator element,

and biasing means acting to maintain the fuel feeding devices operatively connected with the actuating means and with the movable control member whereby movement of the control member operates to vary the quantity of fuel delivered by each fuel feeding device, the improvement which comprises employing actuating means of such a nature that during the time interval existing between the reception and the delivery of a quantity of fuel by one of the fuel feeding devices movementof the control member in the quantity reducing direction is resisted by the biasing means for the said one of the fuel feeding devices and the connections between the remaining fuel feeding devices and the control member are rendered inoperative.

6. In a combination comprising an internal combustion engine regulator having a movable element, fuel feeding mechanism having a plurality of fuel feeding devices, means for actuating the fuel feeding devices to deliver charges of fuel in a predetermined order,'a movable control member cooperating with the fuel feeding devices and with the movable regulator element, and biasing means acting to maintain the fuel feeding devices operatively connected with the actuating means and with the movable control member whereby movement of the control member operates to vary the quantity of the fuel charge delivered by each fuel feeding device, the improvement which comprises employing actuating means of such a nature that movement of the control member in the quantity reducing direction is resisted by the biasing means for a single fuel feeding device and the biasing action exerted on the control member by each fuel feeding device is interrupted during the time interval existing between the delivery of its fuel charge and the next delivery of a fuel charge by the precedently operated fuel feeding device.

7. In a combination comprising an internal combustion engine regulator having a movable element, fuel feeding mechanism having a plurality of fuel feeding devices, an actuating means for each fuel feeding device, a movable control member cooperating with each of the fuel feeding devices and with the movable regulator element, and biasing means acting to maintain each of the fuel feeding devices operatively connected with its actuating means and with the movable control member whereby movement of the control member operates to change the position of each fuel feeding device relative to its actuating means to vary the quantity of the fuel charge delivered by each fuel feeding device, the improvement which comprises employing actuating means of such a nature that during the time interval existing between the reception and the delivery of a. fuel charge by one of the fuel feeding devices movement of the control member in the quantity reducing direction is resisted by the biasing means for the said one of the fuel feeding devices and the connections between the remaining fuel feeding devices and the control member are rendered inoperative.

8. In a combination comprising an internal combustion engine regulator having a movable element, fuel feeding mechanism having a plurality of fuel feeding devices, an actuating means for each fuel feeding device, a movable control member cooperating with each of the fuel feeding devices and with the movable regulator element, and biasing means acting to maintain each of the fuel feeding devices operatively connected with its actuating means and with the movable control member whereby movement of the control member operates to change the position of the fuel feeding devices relative to the actuating means to vary the quantity of the fuel change delivered by each fuel feeding device, the improvement which comprises employing actuating means of such a nature that movement of the control member in the quantity reducing direction is resisted by the biasing means for a single fuel feeding device and the biasing action exerted on the control member by each fuel feeding device is interrupted during the time interval existing between the deliveryof its fuel charge and the next delivery of a fuel charge by the precedently operated fuel feeding device.

9. In a combination comprising an internal combustion engine regulator having a movable element, fuel feeding mechanism having a fuel feeding device for each engine cylinder, a cam for actuating each fuel feeding device,:a movable control member cooperating with each of the fuel feeding devices and with the movable regulator element, and biasing'means acting to maintain each of the fuel feeding devices in engagement with its actuating cam and with the movable control member whereby movement of the control member operates to change the position of each fuel feeding device relative to its actuating means to vary the quantity of the fuel charge delivered by each fuel feeding device, the improvement which comprises employing actuating cams of such shape that during the time interval existing between the reception and the delivery of a fuel charge by one of the fuel feeding devices movement of the control member in the quantity reducing direction is resisted by the biasing means for the said one of the fuel feeding devices and the remaining fuel feeding devices are maintained out of engagement with the control member.

l0. In a combination comprising an internal combustion engine regulator having a movable element, fuel feeding mechanism having a fuel feeding device for each engine cylinder, a cam for actuating each fuel feeding device, a movable control member cooperating with each of the fuel feeding devices and with the movable regulator element, and biasing means acting to maintain each of the fuel feeding devices in engagement with its actuating cam and with the movable control member whereby movement of the control member operates to change the position of the fuel feeding devices relative to the actuating means to vary the quantity of the fuel charge delivered by the fuel feeding devices, the improvement which comprises employing actuating cams of such shape that movement of the control member in the quantity reducing direction is resisted by the biasing means for a single fuel o feeding device and the biasing action exerted on the control member by each fuel feeding device is interrupted during the time interval existing between the delivery of its fuel charge and the next delivery oi a fuel charge by the precedently operated fuel feeding device.

ARTHUR F. STERN. HARVEY W. HANNERS.

CERTIFICATE OF CORRECTION. Patemno. 2,181,286. November 28, 1959.

' ARTHUR F. STERN,- ET AL. It is hereby certified that error ap'pears in the printed speiflcation ofthe above numbered patent requiring vcorrection as follows: Page 5, first column', line 21.1, claim 8, for the word "change' read charge; and that the saLUiL'etters Patent should'be read with this' correction therein that the 'same may conform to the record of the case in the Patent Office..

Signed and sealed this 50th day of January, A. D. 19h0.

Henry van AIfSdBle,

(Sea-l) Acting Commissioner of Patents. 

